To determine how rate of reaction is affected by the surface area of the potato upon adding hydrogen peroxide to it and whether the surface area of the potato affects the height of the froth.

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Introduction

Biology Coursework Aim: To determine how rate of reaction is affected by the surface area of the potato upon adding hydrogen peroxide to it and whether the surface area of the potato affects the height of the froth. Background: Catalase, an enzyme used for removing hydrogen peroxide from the cells, which can be found in potatoes, decomposes hydrogen peroxide into water and oxygen. It is an anabolic reaction, meaning that it is broken down into smaller pieces. Catalase is produced by the cells of the body, and the froth it creates when you add hydrogen peroxide to the cell is because it turns the hydrogen peroxide into water and oxygen gas. The bubbles that are created in the reaction are made up of oxygen. This happens in cells that have been cut, hence the reason the potato reacts upon cutting it up into pieces. Hypothesis: The enzyme and substrate would only come into contact when they are both in the same place, which in this case would be the surface area of the potato. ...read more.

Middle

It is important to notice that I will be measuring the froth as fairly as possible, as it will be deeper on certain parts of the test tube. I will have to make the recordings quickly as there are 5 test tubes and it will take some time to take the recordings of all of them. Results Table: Time (Minutes) A B C D E 1 0.6 1.2 1.0 1.5 1.1 2 1.3 1.6 1.1 1.6 1.3 3 1.4 2.0 1.2 2.5 1.5 4 1.7 2.5 1.5 2.6 2.1 5 2.2 2.9 2.0 2.7 2.2 6 2.5 3.3 2.2 3.2 2.5 7 2.8 3.5 2.5 3.5 2.9 8 3.0 4.0 2.7 3.7 2.9 9 3.2 4.1 3.0 3.9 3.2 10 3.3 4.5 3.1 4.0 3.3 Conclusion: It seems that the larger the surface area, the more reactions that are happening on the surface of the potato at any one time in the experiment between the hydrogen peroxide and the catalase from the cut up piece of the potato, creating more froth showed by the height increase in the table previously shown. ...read more.

Conclusion

Maybe I did not measure it properly and inserted different amounts of hydrogen peroxide in each test tube. For this reason the amount of reactions happening in each test tube could have differed since there was a difference in the ratios in each test tube. Another reason for some of them results being different from others could be because I could not measure the lengths of the potatoes properly. Maybe some of the potato slices were longer than others and therefore more or less cells were present during the reaction depending on the potato and less oxygen bubbles were created during the reaction between the hydrogen peroxide and the cut cells on the surface of the potato slices in each one. The last problem I encountered was the fact that I measured the froth from different places. When the froth was being created, the height was different from different angles of the test tube and therefore I could have measured the results inaccurately. This greatly affects the results but I tried to measure it from the same place as many times as possible to make the experiment fair. ...read more.

Related GCSE Life Processes & Cells essays

This is because the larger the surface area is, the more active site's there are available for substrate to bind to, forming more enzyme-substrate complex's and forming more products in a shorter period of time. By increasing the surface area, you are actually increasing the enzyme concentration, because you have more active sites available.

The diagram below shows this. I will always judge the amount of oxygen collected at eye level so that an accurate result is obtained. The thickness of the tube should always be same at each time so that it is fair on every other experiment.

* Measure them uniformly (3cm) and use a knife to cut them down to size. * Splitting them accordingly - The 1st piece will remain 3 cm, while the 2nd will be split into 2 parts and halved in length. The 3rd, split into 3 parts etc.

19.0 After looking at the results above, I noticed that there had some anomaly in my results by drawing a graph, so I repeated my whole experiment and there are the results I got: Time/ minute Volume of oxygen collected/ cm3 Chip 1 Chip divided into 2 Chip divided into

As a result, the test will become biased. 5 tests will be carried out in each attempt. I will have to stick on using the same potato throughout my whole experiment because the differences in temperature (of the potato) and in varieties can affect the outcome of my experiment.

given off in a measuring cylinder under water (as shown in diagram). I also will chop the ends off of the chips to keep the lengths in proportion and so that if the same experiment was done again then it could be accurately done.

The second reason according to the collision theory is that the temperature can affect the speed of the enzymes reacting with the hydrogen peroxide substrate, too low, and the reaction will be slow because the molecules will be moving

Enzymes can also become inactive by excessive heat. This property of enzymes relates to the fact that they are proteins. Up to about 40 degrees Celsius the rate of reaction starts to increase smoothly, but once at about 45 degrees Celsius the rate of reaction starts to decrease.